Treatment of petrolatum stocks



Patented July 7, 1931- UNITED. STATES PATENT OFFICE AND WILLIAM A. GB'USE, OF WILK JINSBURG, REFINING COMPANY,

or rrrrsnumn, PENN- TREATMENT OF PETROLAT'UM STOCKS No Drawing. Application filed June 5,

This invention relates to the treatment of petrolatum stocks and it comprises a process of separating petrolatum stock into its several component parts' such as waxy matter, asphal- I tie material, resins and viscous oil of low cold ,test and low carbon content, wherein petrolatum stock, separated from cylinder stock in the ordinary way, by cold settling of heavy steam refined petroleum oils with the aid of 1 naphtha, is dissolved in'butyl alcohol to form a solution, said solution is cooled to separate products other than contained heavyoil, the separated material is removed and the mineral oil recovered from the remaining. solution; cooling'and settling advantageously being accomplished in a succession of steps with the'separation and removal of a single component at each step; all as more fully hereinafter setforth and as claimed.

It'has been common practice since early days of the petroleum refining art toremove the wax content of certain heavy steam refined petroleum oils by dissolving or diluting sai oil in petroleum naphtha and chilling the mixture, whereupon the wax content separates out of solution. The waxy material so separated has long been known as petrolatum stock and the petrolatum "or petroleum jelly of commerce has been produced by refining this material.

The described cold settling process is used in the production of heavy oils of low wax content and oils which have a low carbon residue test. Of recent ,years the demand for these extremely viscous, low cold test and low carbon test oils has been such as to result in the incidental production of a quantity of etrolatum stock greatly out of proportion to the market demand for petrolatum. As a result it is common to convert muchof this petrolatum stock into gasoline by cracking processes.

We have found that petrolatum of the character described contains a microcrystalline 45 wax of the eneral character of ceresin and, like ceresin, is useful for many technical purposes. It is accompanied by certain resinous and asphaltic or gummy bodies which must be separated in order to develop its character.

In the petrolatum stock formed by the ded duce'd is added butyl alcohol.

' moved by settling or with 1928. Serial 110,283,122.

scribed cold settling process these various bodies are accompanied by about half their volume of the original heavy oil.- A petrolatum stock made by ordinary cold settling of heavy steam refined petroleum oils with the aid of petroleum naphtha, ordinarily carries 20 per cent or more of the new high melting point waxy material. The remainer consists of resins, asphaltic materials, etc.

In the present invention it is the object to recover the described valuable ceresin-like wax and also high grade heavyoil as well as a resinous and asphaltic material as a byproduct.

In a practical embodiment of our invention we start with the described petrolatum stock produced by cold settling heavy steam refined petroleum oils with the aid of petroleum naphtha. This petrolatum stock often carries as high as 25 per cent of the naphtha used in the cold settling process. This is first removed by steaming.

From 4 to 6 parts alcohol are added, the; proportion depending somewhat on the character of the To the stock so prostock. Admixture of alcohol is effected ata temperature suflicient to produce complete solution of the stock in the alcohol. This temperature is advantageously around 180 F. The solution is then cooled somewhat, say to a temperature of 140 F. At this temperature, the resins and asphaltic material separate out as a distinct layer which is rethe aid of a centrifuge. The remaining chilled to about ordinary room temperature, say, to about 70 F. At this temperature a large part of the wax content separates out and this is removed by settling or with the aid of a centrifuge. The solution, now deprived of its resins and asphaltic material and of part of its wax content, is chilled, advantageously to a temperature of from 15 F. to 0 F., whereupon additional wax separates out. This is removed by. centrifuging. The two wax fractions so obtained have somewhat different characteristcis; remaining after the last centrifuging is distilled to remove and recover the butyl alcohol. The residue is a highly viscousmineral oil solution is next The solution 25 fined by various processes naphtha preliminarily.

The foregoing process as described takes the resins and asphaltic materials outin one cooling and separation with subsequent removal of wax in the two stages. It is how- 5 ever possible to separate and remove all of the wax in a single stage, obtaining the two fractions together. I/Vhether the single stage or two-stage separation is used depends upon the particular character of the wax desired.

The cooling may be effected in a single stage without any intermediate removal of solid matter. In this event, the resins, the asphaltic material and the wax come out together as a composite material. This may be reto give material of the general character of Montan wax. The waxes separated by single stage or twostage separation vary somewhat in melting pointsand other characteristics. They are high melting but have no sharp melting point. While of crystalline character when pure, the crystallinity is not as highly developed as in paraffin wax and the general properties are quite different. As stated, the

wax resembles ceresin. rather brown in color. the color is not disadvantageous. Where a lighter product is wanted, the wax may be refined by acid treating and the use of clay.

Generally the asphaltic and resinous fractions carry considerable proportions of wax and it is sometimes worth while to repeat the Generally the wax is process of dissolving in butyl alcohol and fchilling; For example, the asphaltic and resinous material separated may be extracted several times with butyl alcohol, using each time,- say, 0.8 parts by weight of the a ohol. In,a modification of this invention, after resinsand asphaltic material have been re- 0 moved and prior to the last cooling and separation of wax, acetone is added. The addition of acetone at this point effects a more .complete'separation of the wax and the wax is of somewhat purer character. The oil recovered from the solution has a lower pour In one embodiment ofthis invention, we treated a petrolatum stock produced by the ordinarycold settling with naphtha of an oil of the following tests: gravity, 23

A. P. I., at F.; viscosity, 150 sec., Saybolt, at 210 F.; flash point, 510 11'; pour oint, F. carbon residue test, 4.0 per cent.

is petrolatum stock was steamed and sub Jack: to the process here disclosed. There For many purposesmaterial, removing adding a was recovered about'20 per cent of heavy mineral oil having a density of 0.92, a pour test of 25 F. and a viscosity of 127 seconds, Saybolt, at 210 F. Its Conradson carbon residue test was about that of an ordinary bright. stock, viz. 2.7 per cent. On the same stock and proceeding in the same manner, ex; cept for the addition of acetone before the last wax separation, an oil was obtained having characteristics the same as the oil just mentioned but the pour test was 10 lower. This reduction of pour test was efiected by using 15 parts of acetone. to 25 parts of solution. I

By cooling the original solution of petrolatum stock in butyl alcohol to a temperature at which only the resins and asphaltic material are thrown out a material is obtained which on distilling ofi' butyl alcohol can be used to produce a superior quality of petrolatum'freer of resins and asphaltic material than that produced by ordinary means.

While the removal of separated matter has in each case been described as being accomplished with the aid of a centrifuge, removal can also be efiected by ordinary gravity settling. The advantage offered by the use of centrifuges is that the settling time is shortened and the separation is so improved as to permit operating the process as a practically continuous one.

The removal of wax in a single stage or in two or more stages is, as stated to some extent an economic matter depending on the cost of centrifuging on one hand as against the ease of removal and simplification of the chilling process on the other hand. The removal of the waxes and resins separately or jointly is an economic matter, depending on their value.

Secondary butyl alcohol can be substituted in this process for the normal buytl alcohol and will give about the same results.

Where the main object is the recovery of high grade oil from petrolatum stock by the addition of butyl alcohol as described the mixture is chilled in a single stage and the separated matter removed. In this event the temperature to which the" solution is cooled is dictated by the cold test desired in the-recovered oil. 1

What we claim is:

1. The process of recovering heavy mineral oil from petrolatum stock which comprises adding a butyl alcohol to petrolatum stock at a temperaturesuificient to 'efi'ect solution, cooling the solution to produce a separation of asphaltic, resinous and waxy the so separated mate.- rial, distilling ofi utyl alcohol and recovering the heavy mineral oil residue.

2. The process of recovering heavy mineral oil of low wax content and low carbon residue test from petrolatum stock whichcomprises tyl alcohol to petrolatum stock and waxy tion, cooling said under conditions forming a solution, chilling said solution to a low temperature an effecting a separation of asphaltic, resinous material, removing the so separated material from the liquid, distilling off butyl alcohol and recovering the heavy mineral oil residue.

3. The process of treating petrolatum stock which comprises adding a butyl alcohol to petrolatum stock at such a temperature as will eflect solution, cooling said solution to a temperature suflicient to separate contained resins and asphalts and enough 0 the wax to produce a product liquid at room temperature, removing the so separated material and distilling the butyl alcohol out of the remaining liquid to produce a liquid residue containing heavy mineral oil.

4. The process of separating petrolatum stock into its component parts and recovering wax and, by-products which comprises adding a butyl alcohol to petrolatum stock at a temperature sufficient to effect solution, cooling said solution to a temperature suflicient to separate contained resins and asphaltic material while not so low as to separate wax, removing the separated material, further cooling the liquid to a temperature suflicient to separate wax, removing the separated wax and distilling the butyl 'al-' cohol out of the remaining liquid to recover heavy mineral oil.

5. The process of separating petrolatum stock into resins and asphalts, waxand oil of low wax and carbon content which comprises adding a butyl alcohol to petrolatum stock at such temperature as will effect solusolution to a temperature sufficient to separate contained resins an asphaltic material while not so low as to separate a substantial amount of wax, removing the separated material, adding acetone to the liquid, further cooling the liquid to a temperature whereby wax is separated, removing the separated wax and distilling the butyl alcohol and acetone out of the remaining liquid to produce a residual heavy mineral oil of low wax and carbon content.

6. The process of separating petrolatum stock into resins and asphaltic material, wax and oil of low wax content and low carbon residue test which comprises adding a butyl alcohol-to petrolatum stock at such temperature as will effect solution, cooling said solution to a temperature su cient to separate contained resins and asphaltic materials while not so low as to separate a substantial amount of wax, removlng the separated material, similarly removing the wax from residual liquid by cooling in a plurality of stages with separate removal of wax in each stage, adding acetone to the, liquid immediately before the last stage of wax separation and distilling the butyl alcohol and acetone out of the liquid from which the resins and asphaltic material and waxes have been removed, to produce a residual heavy mineral oil of low wax content and low carbon residue test.

7. The process of separating petrolatum stock into resins and asphaltic material, wax and oil of low wax content and low carbon residue test which comprises dissolving petrolatum stock in a butyl alcohol at a temperature of approximately 180 F., cooling said solution to a temperature of approximately 140 F. to produce a separation, removing separated material, further cooling the liquid to a temperature below 32 F., removing the separated material and distilling the butyl alcohol out of the remaining liquid to produce a residual heavy mineral oil of low cold test and of low carbon residue test."

8. The process of separating petrolatum stock into resins and asphaltic material, wax and oil of low wax content and low carbon residue test which comprises dissolving petrolatum stock in a butyl alcohol at a temperature ofapproximately 180 F., cooling said solution to a temperature of approximately 140 F. to produce a separation, removing separated material, adding acetone to-the liquid, further chilling the liquid to a temperature below 32 F. and removing the separated material, and distilling the butyl alcohol and acetone out of the remaining liquid to produce a residual heavy mineral oil of low cold test and of low carbon residue test. a

In testimony whereof, we have hereunto alfixed our signatures at Pittsburgh, Pennsylvania, this 2nd day of June, 1928.

BENJAMIN L. SOUTHER. WILLIAM A. GRUSE. 

